Managing Rats in Sewers | Effective Strategies

If you live in an urban area, you’re likely familiar with the sight of rats scurrying around the streets.

However, what you may not know is that these rodents often make their homes in the sewers beneath our feet.

While they may seem harmless down there, rats in sewers can pose a real threat to your home and health.

In this article, we’ll explore the ins and outs of rats in sewers, including how they get in and how to get rid of them.

We’ll also cover the signs of a rat infestation and how to prevent them from becoming a problem in the first place.

Whether you’re dealing with an existing rat problem or just want to be prepared in case one arises, keep reading to find out more.

What Are Sewer Rats

Sewer rats, also known as brown rats or Norway rats, are a type of rodent that is commonly found in urban areas around the world.

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They are medium-sized rats that can grow up to 10 inches in length, not including their tail. Sewer rats have brown or gray fur, small ears, and a pointed snout.

These rats are social animals that live in large groups called colonies. They are known for their excellent sense of smell, which they use to locate food and avoid danger.

Sewer rats are well adapted to life in the urban environment and can be found in a variety of habitats including buildings, parks, and sewers.

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Why Are There Rats in Sewers?

Sewer rats have adapted to live in the dark, damp environment of the sewer system and are attracted to sewers for several reasons.

Why Are There Rats in Sewers?

Food Sources

  • Sewers provide rats with an abundant supply of food.
  • The discarded waste and debris that accumulate in these underground passages create an enticing buffet for these scavengers.
  • From food scraps to improperly disposed edibles, rats find a treasure trove of sustenance, ensuring a steady food source to sustain their population.

Shelter and Nesting Opportunities

  • The dark and secluded environment of sewers offers rats a haven to establish their nests and raise their young.
  • The intricate tunnel networks provide protection from predators and harsh weather conditions, making sewers an ideal spot for these urban rodents to thrive.

Proximity to Humans

  • Rats are highly adaptable to living alongside humans.
  • The interconnected nature of the sewer system brings them in close proximity to urban areas, allowing easy access to food and shelter from buildings and other structures.

Easy to Navigate

  • Rats are skilled navigators and can easily find their way around complex urban landscapes.
  • Their exceptional sense of smell and memory aids them in memorizing routes, making it effortless for them to explore various areas, including sewers.
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How Do Rats Get in Sewer Lines?

Rats are cunning creatures, and finding their way into sewer lines is a piece of cake for them.

Here’s how they manage to infiltrate the underground passages.

How Do Rats Get in Sewer Lines?

Cracks, Holes, and Broken Pipes

  • Rats are experts at squeezing through tiny openings.
  • If there are cracks or holes in sewer lines or manhole covers, they can easily slip through these gaps, gaining access to the sewer system.
  • Sewer lines with damaged or broken pipes offer an open invitation to rats.
  • These clever rodents can detect weaknesses in the infrastructure and exploit them as entry points.

Connections to Buildings

  • They can use these connections to move between the sewer system and human habitations.

Sewer Grates and Vents

  • Sewer grates and vents, although designed to keep debris out, can sometimes become vulnerable entry points for rats.
  • These rodents can skillfully maneuver their way through these structures.
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Through the Toilet

  • Yes, you read that right! In rare instances, if sewer lines are damaged or improperly connected, rats can emerge through toilets, surprising unwary homeowners.
Rats have an extraordinary sense of smell, allowing them to follow scent trails left by other rats or the presence of food. 

These trails can lead them straight into the sewer lines.
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Signs of Rats in Sewers

Rats are often difficult to detect in the sewer system, but there are some signs that can indicate their presence.

Here are a few things to look out for.

Signs of Rats in Sewers

Rat Droppings

  • Fresh droppings indicate recent activity, while older ones may suggest a long-standing infestation.
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Gnaw Mark

  • Rats have strong teeth and are known for their ability to gnaw through a variety of materials, including pipes and wires.
  • If you notice gnaw marks on pipes or other surfaces in the sewer system, it may be a sign of rat activity.

Pawprints and Tail Marks

  • Rats can leave footprints and tail marks in mud or dusty areas around sewer lines, especially after rain or when sewer access points are opened.

Unusual Sounds or Smells

  • If you hear unusual sounds, such as scratching or squeaking, or notice unusual smells, such as the smell of urine or feces, it may be a sign of rat activity.
On top of the signs mentioned earlier, you may also notice loose or disturbed soil and nests made of shredded materials, such as paper, cloth, or twigs. 

These can be additional indicators of rat activity in the sewer system.

Are Sewer Rats Dangerous?

Sewer rats, like any wild animal, can pose certain risks to human health and property.

While they are not inherently aggressive towards humans, their presence in urban areas can lead to various concerns.

Here’s what you need to know about the potential dangers associated with sewer rats.

 rats in sewers | Are Sewer Rats Dangerous?

Disease Carriers

  • One of the primary concerns is the potential for disease transmission.
  • Contact with rat droppings, urine, or saliva can lead to health issues in humans, including gastrointestinal problems and infections.
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Property Damage

  • Rats are persistent gnawers, and their constant chewing can lead to property damage.
  • In sewers, they may damage pipes and cables, posing a risk of infrastructure disruption.
  • If they find their way into buildings, they can cause harm to electrical wiring, wooden structures, and insulation.
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Food Contamination

  • When they access food storage areas, pantries, or restaurants, they can leave behind bacteria and pathogens, potentially causing foodborne illnesses in humans.

Allergic Reactions

  • Rat allergens can trigger allergic reactions in sensitive individuals.
  • Airborne particles from rat fur, droppings, or urine can exacerbate respiratory issues for people with allergies or asthma.
While sewer rats themselves may not directly harm humans, their presence can attract other predators, such as snakes or larger mammals, to the urban environment, potentially leading to unexpected encounters.

Who is Responsible for Rats in Drains

Determining responsibility for rats in drains can be a complex matter, as it often depends on the specific circumstances and jurisdiction.

Here are some key factors that may play a role in identifying who is responsible.

Rats in sewers Who is Responsible for Rats in Drains

If You Own the Property

If you own the property, you have a legal obligation under the Prevention of Damage by Pests Act 1949 to keep your premises rodent-free.

This means you are responsible for addressing rat issues within your property’s drains.

If rats are coming up from the sewers beyond the boundary of your property, water companies are obliged to assist you.

However, if the rats are escaping from your drain, then you will be responsible for the necessary repairs.

If You Rent the Property

If you do not own your property, the landlord will usually be responsible for rats in the drains and should contact a pest control specialist at the earliest opportunity.

It is the landlord’s duty to ensure that the property remains free from rat infestations and to take appropriate measures if such issues arise.

Municipal Authorities

In urban areas, where sewer systems are part of the municipal infrastructure, the responsibility for managing sewer rats often falls under the jurisdiction of the local government or municipal authorities.

They may be tasked with regular maintenance and pest control measures to prevent rat infestations in the public sewer system.

However, determining responsibility can be complicated in some cases, such as in multi-unit buildings or shared spaces. 

In these situations, it is important to work with other property owners or occupants to develop a plan for managing rat populations and maintaining the sewer system.
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How to Get Rid of Rats in Sewers

Dealing with rats in sewers requires a strategic and systematic approach.

Here are effective methods to help you get rid of these pests.

How to Get Rid of Rats in Sewers

Use Rat Traps

  • Placing rat traps strategically along sewer access points can help catch and remove rodents.
  • Snap traps quickly kill rats, while live traps allow for their safe release elsewhere. Glue traps capture rats alive, allowing for proper disposal.

Use Rat Poison

  • Rat poison can be an effective way to control rat populations in sewers.
  • Place the poison in bait stations near the sewer entrance or in areas where rats are known to frequent.
  • Be careful when using rodenticides, as they can be harmful to humans and other animals. Proper placement of bait stations away from children and pets is crucial.
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Professional Pest Control

  • If you’re having difficulty controlling rat populations in sewers, consider working with a pest control professional.
  • They have the expertise, tools, and knowledge to safely and effectively address rat infestations in sewers
  • They can help to assess the situation and develop a plan for controlling rat populations in the sewer system.
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How to Prevent Rats From Re-Entering Sewer Pipes After Removal

After removing rats from the sewer system, it’s important to take steps to prevent them from re-entering.

Here are some ways to prevent rats from re-entering sewer pipes.

Repair any Cracks or Gaps

  • Inspect the sewer pipes thoroughly for any cracks, gaps, or damage.
  • Promptly repair these vulnerabilities using suitable materials like cement, caulk, or pipe sleeves.
  • Sealing off these entry points will deter rats from accessing the sewer system.

Install Rat Guards

  • Make sewer access points extra secure with a multi-layered approach.
  • Install rat guards made of tough metal or plastic to keep rats from climbing back up through the pipes.
  • Use one-way valves, allowing wastewater to flow out but blocking rats from coming back in.
  • Cover sewer vents and access points with a fine mesh that rats can’t chew through to create a strong barrier.

Remove Rats Living Sources

  • Prevent rats from finding shelter near the sewer pipes by getting rid of places they could build nests.
  • Rats are attracted to areas with food and water sources.
  • Removing any potential food and water sources near the sewer system, such as garbage or standing water, can help to reduce the attractiveness of the area to rats.

Plug Up Disused Pipes

  • If there are any pipes that are no longer in use, make sure to seal them off.
  • Rats might use these neglected openings to get back into the sewer system.
  • Use materials like concrete or metal caps to effectively block these unused pipes.
By following these simple steps, you create a strong defense against rats trying to re-enter sewer pipes.
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Final Thoughts

If you live in or near an urban area, it’s possible that rats may be present in the sewer system. These rodents can cause damage to property and pose health risks to humans.

To manage rat populations in the sewer system, you can use a variety of methods such as traps, rat poison, and sealing entry points.

In addition, keeping the sewer system clean and removing potential food and water sources can help discourage rats from taking up residence.

You can prevent them from re-entering by repairing any cracks or gaps in the piping, installing rat guards and one-way valves, using rodent mesh, removing rodent living sources, and plugging up disused pipes.

By being proactive and taking action to control and prevent rats in the sewer system, you can minimize the risk of rat-related issues and help to maintain a safe and healthy environment for everyone.


What attracts sewer rats to your house?

Sewer rats are drawn to houses by food sources, open trash containers, and accessible shelter.

What causes rats in sewers?

Rats find their way into sewers due to the abundance of food and suitable nesting spots.

What do rats eat in sewers?

In sewers, rats feed on discarded food, organic waste, and other debris.

Do sewer rats swim?

Yes, sewer rats are excellent swimmers and can navigate through water with ease.

Are sewer rats smart?

Yes, rats are highly intelligent creatures, capable of learning and problem-solving.

Do rats sleep in sewers?

Yes, rats sleep for short periods throughout the day, including in sewers.

Can a sewer rat come up a toilet?

Rats coming up toilets is relatively rare, but it can happen in certain situations.

Can a rat lift a toilet seat?

Rats cannot lift a toilet seat due to their size and physical limitations.

Can I flush a dead rat down the toilet?

Flushing a dead rat down the toilet is not recommended, as it can cause plumbing issues.

What diseases do sewer rats carry?

Sewer rats can carry diseases such as leptospirosis, salmonella, and hantavirus.

What happens if a sewer rat bites you?

A rat bite can transmit diseases and may require medical attention to prevent infection.

Resources – (for further reading) – Prevention of Damage by Pests Act 1949

King County (.gov) – Diseases from rodents, pocket pets and rabbits


I'm Ernest M Noah, the founder of I have years of experience as an exterminator in Texas and Idaho, and I'm passionate about educating people on how to deal with pest problems effectively and safely.